How can I create a realistic stack of pages?
You can uv unwrap your volume/pad from the top with project from view, so that you will have the yellow colors bleeding along the sides as in your reference, as long as you keep the UV inside the texture. Then you can use a normal input combined to a dot node to separate the vertical sides and the top face and use this output to create a variation of the texture (adding some vertically compressed noise for page division, multiplied to the image texture and a bit desaturated). This texture is then plugged into a basic diff+glossy mixed shader. Big advantages here, you are sure the colors on the side are in good position regards to the top, and you can change the whole thing by tuning the uv or changing the texture !



Blend is here